Strange and unconventional isotope effects in ozone formation

The puzzling mass-independent isotopic enrichment in ozone formation contra sts markedly with the more recently observed large unconventional mass-depe ndent ratios of the individual ozone formation rate constants in certain sy stems. An RRKM (Rice, Ramsperger, Kassel, Marcus)-based theory is used to t reat both effects. Restrictions of symmetry on how energy is shared among t he rotational/vibrational states of the ozone isotopomer, together with an analysis of the competition between the transition states of its two exit c hannels, permit the calculation of isotope effects consistent with a wide a rray of experimental results.